Heretofore, feature capability and appearance of a household sewing machine is determined very early in the manufacture of the sewing machine. For example, a specific pattern capability is built into a given sewing machine, requiring the inclusion of specific pattern cams. Production of a line of machines having less pattern capability requires the elimination of some of these specific pattern cams with corresponding changes in the pattern selection system and possibly in the sewing machine frame. A change in appearance and method of control also required more or less extensive modification to the sewing machine frame.
Similarly, the addition of features such as single pattern sewing capability, safe twin needle sewing capability, change from square end to round end buttonhole, or, change in preset stitch parameters require additions or changes to sewing machine components and to the sewing machine frame which, depending on the feature added, may be drastic and expensive in the prior art sewing machines.
The aforementioned method of manufacture tends somewhat to inhibit freedom of choice in adding machine features, in adding or deleting sewing patterns available, in changing type of control such as from push button controls to dial controls, and in changing appearance of the sewing machine wherein the change desired would require extensive modification. What is required is a ready means of changing the feature capability, method of control and/or appearance of a sewing machine without the requirement for radical changes to the sewing machine frame or components heretofore required.